HEAT oil in a large pot or deep fryer to 350°F (180°C). Cut each wiener into six pieces. Working in batches, dip each piece of wiener into batter then deep fry for 2-3 minutes, turning once until golden brown. Remove from oil and drain on a paper towel lined plate.

Sweet and Sour Mustard Sauce:

COMBINE sugar and mustard in a heavy saucepan. Stir in vinegar and bring to a boil. Reduce heat to low and slowly add a small amount to the mixture to the eggs, stirring constantly. Add the tempered egg mixture back to the saucepan and continue to stir until thickened. Remove from heat and stir in butter.